Christmas Bird Count Tirimbina 2011

by: Cristhian Ureña.

Last November 17th, 2011 Tirimbina Biological Reserve was part, once again, of the Christmas Bird Count organized by La Selva Biological Station (OTS), which takes place every year during the month of December and Tirimbina was included in this bird count. The count takes place through elevations from 35m through 1070m. The aim of these counts is to work on the monitoring and census of resident and migratory birds.

According to La Selva organizers there were more participants this year, which shows there is a growing interest in birdwatching. At Tirimbina Reserve we covered 4 routes, covering 9.5 km, with 6 hours of continuos sampling during the day and one hour of nocturnal monitoring. These routes came from 4 different points in order to cover a wider variety of hábitats like primary forest, forest edge, secondary forest, rivers, streams, thicket áreas, gardens and cacao plantations inside the 345 ha of the Tirimbina Reserve.

The activity was shortened due to bad weather conditions. The rainfall started around 9am, strong and continuos until 1pm. For this reasons the participants thought they would see fewer birds; but at least it was posible to count from 4am until 9am when most of the activity took place.

There were 8 people participating who counted a total of 146 bird species. The unique species for the Reserve were the Agami Heron (Agamia agamia), ione of the most spectacular herons for its colors and it is normally found only in few locations around the country. The Vermiculated Screech Owl (Megascops guatemalae) is a resident specie present in this forest. It is common to hear the call but not common to see it. We can not discount the migratory birds coming from the north. Normally they visit us from September to April. Most of these species spend the Winter in the tropics, using our country as a crossing point or temporary residence. Later they go back to the temperate zones to reproduce and nest. These counts during the months of November and December help us to monitor the movement of the different altitudinal and latitudinal migratory species. The first ones are the species moving from high elevations of cloud forest and pre-montanes to lowlands like humid forests searching for food and they migrate during these months. Therefore during this time of the year there is more opportunity to see more birds and we also have species from North America.

So far in Costa Rica 893 bird species have been recorded. According to the Costa Rica Ornithology Union’s new records Tirimbina Reserve is a bird watching site that is very important for seeing a lot of species, among these, migratory raptors that fill the skies during September and October. Thousands of them pass through during this time of the year and even if we don’t see them during the count it is important to highlight this phenomenon to show how these and other species use Tirimbina as their temporary residence or crossing point. It is valid to keep working on these counts for new records, the importance of forest conservation and with that the conservation of the bird life.